1. Field of the Invention
The present invention relates to a switch contact structure.
2. Description of the Related Art
Hitherto, the switch contact structure of this type includes, for example, the one shown in FIG. 9 and FIG. 10, or the one shown in FIG. 11, which is disclosed in JP-A-11-250772. As shown in FIG. 9, a plurality of fixed contacts 202 are provided on a substrate 201, and a movable block 203 is disposed so as to be movable along the substrate 201 in the directions indicated by arrows G and H.
The movable block 203 is provided with a plurality of movable contacts 205 corresponding to the fixed contacts 202. The movable contact 205 includes a resilient arm 207 supported by the movable block 203 and a curved contact portion 209 at the distal end of the resilient arm 207.
The movable block 203 is provided with an engaging section 211, which projects upward from an elongated hole 215 formed on the partition wall 213. A control rod engages the engaging section 211, and thus the movable block 203 is capable of linear movement on the substrate 201 in the directions indicated by the arrows H and G in conjunction with the action of the control rod. The linear movement of the movable block 203 allows the contact portions 209 of the movable contacts 205 to be brought into and out of contact with the fixed contacts 202 on the side of the substrate 201 in a prescribed state to create the ON state and the OFF state.
Resiliency of the resilient arm 207 formed of conductive metal leaf spring material allows the contact portion 209 to make resilient contact with the fixed contact 202 to maintain a desirable contact pressure. In addition, pressing the movable block 203 toward the partition wall 213 by the resilient arm 207 may prevent rattling of the movable block 203.
The example shown in FIG. 11 is constructed in such a manner that the movable contact 219 is stored in a recess 217 on the movable block 203 via a contact spring 221. Therefore, in the case shown in FIG. 11, a resilient force of the contact spring 221 allows the movable contact 219 to be brought into resilient contact with the fixed contact 202, and simultaneously presses the movable block 203 against the partition wall 213 to prevent rattling of the movable block 203.
However, in the examples shown in FIG. 9, FIG. 10 or FIG. 11, since the movable contact 205 or the movable contact 219, and the contact spring 221 are provided separately from the movable block 203 formed of resin, the number of components increases and thus assembly and parts management are very complicated.
In the case of the movable contact 205 as shown in FIG. 10, since the resilient arm 207 is disposed obliquely with respect to the movable block 203, a resilient force exerted on the movable block 203 may be biased and thus it cannot prevent rattling of the movable block 203 satisfactorily.
Furthermore, in the example shown in FIG. 11, though the contact springs 221 on both sides gives a well-balanced resilient force to the movable block 203, the number of the contact spring 221 and the like significantly increases, and thus there arises such a problem that assembly and parts management become complicated. In addition, when assembling the movable contact 205 to the movable block 203, the movable contact 205 is liable to be dropped from the movable block 203.
In the example shown in FIG. 10, the separate movable contact 205 is mounted on the movable block 203, and in the example shown in FIG. 11, the separate movable contact 219 and the contact spring 221 are mounted on the movable block 203. Therefore, there arises such a problem that the movable contact 219 and the contact spring 221 are liable to be dropped at the time of assembly, and the movable block 203 is liable to rattle at the time of operation.
Accordingly, it is an object of the invention to provide a switch contact structure including a reduced number of components, thus facilitating assembly and parts management, and preventing the movable block reliably from rattling
The invention according to (1) is a switch contact structure comprising a substrate, a movable block disposed so as to be movable along the substrate, a fixed contact mounted on the substrate, and a movable contact mounted on the movable block, wherein the movable contact is brought into and out of contact with the fixed contact by the movement of the movable block along the substrate, characterized in that the movable block is provided with a resin spring portion formed integrally therewith for urging the movable contact toward the substrate, and the movable contact plated or printed on the surface facing toward the aforementioned substrate.
The invention according to (2) is a switch contact structure comprising a substrate, a movable block disposed so as to be movable along the substrate, a fixed contact mounted on the substrate, and a movable contact mounted on the movable block, wherein the movable contact is brought into and out of contact with the fixed contact by the movement of the movable block along the substrate, characterized in that the movable block is provided with a resin spring portion formed integrally therewith for urging the movable contact toward the substrate, and the resin spring portion is provided with the movable contact plated or printed on the surface facing toward the substrate.
The invention according to (3) is a switch contact structure as set forth in (2), characterized in that the movable block comprises a base portion having a engaging section for coupling, and a resin spring portion of substantially diamond shape in cross section formed integrally with the base portion, and the movable contact is plated or printed on the resin spring portion at the top of the diamond shaped cross section.
According to the invention as set forth in (1), since a substrate, a movable block disposed so as to be movable along the substrate, a fixed contact mounted on the substrate, and a movable contact mounted on the movable block are provided, the aforementioned movable contact may be brought into and out of contact with the fixed contact by moving the movable block along the substrate.
Since the movable block is provided with the resin spring portion formed integrally therewith for urging the movable block toward the substrate, and the movable contact plated or printed on the surface facing toward the substrate, a separate contact spring for bringing the movable contact into resiliently contact with the fixed contact is not necessary, whereby the number of components may be reduced to facilitate assembly and parts management, thereby reducing the costs.
This arrangement allows reliable resilient contact between the movable contact and the fixed contact, and this reliable contact ensures prevention of loose connection. Furthermore, since the resin spring portion is integrally formed with the movable block, the spring member is prevented from being dropped when being assembled and occurrence of rattling of the movable block can be reliably prevented.
According to the invention as set forth in (2), since a substrate, a movable block disposed so as to be movable along the substrate, a fixed contact mounted on the substrate, and a movable contact mounted on the movable block are provided, the movable contact may be brought into and out of contact with the fixed contact by moving the movable block along the substrate.
Since the movable block is provided with the resin spring portion formed integrally therewith for urging the movable block toward the substrate, and the resin spring portion is provided with the movable contact plated or printed on the surface facing toward the substrate, a separate contact spring for bringing the movable contact into resiliently contact with the fixed contact is not necessary, whereby the number of components may be reduced to facilitate assembly and parts management, thereby reducing the costs.
Since the movable contact is plated or printed on the surface of resin spring portion facing toward the substrate, reliable resilient contact between the movable contact and the fixed contact is achieved, and this reliable contact ensures prevention of loose connection. Furthermore, since the resin spring portion is integrally formed with the movable block, occurrence of rattling of the movable block can be reliably prevented.
According to the invention as set forth in (3), in addition to the effect of the invention in (2), since the movable block comprises, a base portion having a engaging section for coupling, and a resin spring portion of substantially diamond shape in cross section formed integrally with the base portion, and the movable contact is plated or printed on the resin spring portion at the top of the diamond-shaped cross section, the well-balanced resilient force of the resin spring portion of substantially diamond shape in cross section allows further reliable resilient contact between the movable contact and the fixed contact, whereby the reliable contact pressure ensures prevention of loose contact. Furthermore, since the resin spring portion can generate a well-balanced resilient force, rattling of the movable block is prevented further reliably.